Don Sleeth, having been an HVAC Contractor for 12 years, leaves to devote his full attention to his new company
HVAC Computer Systems Ltd.. The success of his computer programs is a direct result of his complete
knowledge of what a contractor is and needs. He is a Contractor first, programmer second.

1982

York Canada introduces the York SmartChart. This handheld Computer/Printer becomes the hit of
the spring marketing tour.

1983

York Borg-Warner introduces the York SmartChart throughout the U.S. and adds a Manual J sixth edition Residential Load
Calculation program. These programs, written by Don Sleeth president of HVAC Computer Systems Ltd. set the standard for
ease of use.

1984

Rheem and Ruud contract with HVAC Computer Systems to offer a customized version to their
dealers through a volume awards program. Demand is so strong
that the programs are soon offered for direct purchase through their extensive distributor network.
The system is sold under Rheem The Master and RUUD The Facts trade names.

1985

HVAC-Calc version 1 is offered directly to contractors by HVAC Computer Systems Ltd.

1987

Lennox Industries Inc. contracts with HVAC Computer to develop a second generation of computer programs
for the handheld system. They are marketed as the Lennox Logic Jr II.

1989

Armstrong Air Conditioning Inc introduces the Armstrong Analyzer, again a customized version of Don's easy to use
computer programs for HVAC Contractors.

1990

HVAC-Calc version 2 is offered directly to contractors by HVAC Computer Systems Ltd.

1997

HVAC-Calc version 3, operating on the Win95 or Windows NT Platform is introduced. Building on
28 years of HVAC experience, this easy to use Residential Load program again
sets the standard for Ease of Use and Speed.

1998

HVAC-Calc Commercial 4.0 is introduced, bringing the same "Contractor Friendly" theme to the commercial load
field. Both programs are built to be compatible with all Microsoft Windows systems including the proposed 32 bit operating systems of the future.

2000

HVAC-Calc Residential 4.0 is introduced. This version adds the ability to copy jobs from one computer to another
and represents a solid platform upon which we can add new features as time goes on.

2000

Don recognizes the need for HVAC contractors to have a place to get together in Cyberspace
and learn and help each other. He starts an online community, HVAC-Talk.

2001

With the growing popularity of the Internet, more and more Home Owners are downloading
HVAC-Calc Residential 4.0 and are asking for a less expensive "Home Owner" license. With
the ease of use of this program and the clear instruction manual that is included, home owners
want to calculate their own loads. HVAC Computer Systems introduces a $49 two month
license for non-profit use by individuals to do their own homes.

2001 to 2007

In keeping with Don's roots in the HVAC business and the "Contractor Friendly" code we follow,
over 80 updates and additions to the programs have been made, all available for free to our
customers.

2007

More updates to add requested features and to ensure program compatibility
with the new Microsoft Vista operating system.

2015

33 years and still going strong! Changes were made to the programs to make them work
smoothly on Microsoft Windows 7 and Windows 8.